An articulated robot for welding, which is arranged on a production line for manufacturing automotive vehicle bodies, is equipped with an end effector (welding gun) on the distal end of an arm, wherein by driving the arm, the end effector is moved to respective working points (respective welding spots) to carry out spot welding. An orientation of the end effector at the respective working points and a movement path of the end effector between two of the working points are preset beforehand as teaching data. As a teaching data setting method, although both on-line teaching and off-line teaching are known, in recent years, a demand for off-line teaching is growing. In such circumstances, techniques for preparing teaching data with high efficiency are desired.
In Japanese Patent No. 3647404 (hereinafter referred to as Patent Document 1), a technique is disclosed for automatically preparing teaching data relating to the movement path of an end effector. More specifically, a technique is disclosed for automatically setting a movement path (short range motion path) for pulling an electrode of the end effector from inside a workpiece to the outside of a workpiece, and a movement path (wide range motion path) for moving the end effector between two working points.
In Japanese Patent No. 4000306 (hereinafter referred to as Patent Document 2), a technique is disclosed for automatically preparing teaching data relating to the orientation of an end effector at respective working points. More specifically, a technique is disclosed in which, after having corrected orientation data of an end effector at respective working points of arbitrary sites, for example, a window frame, of a first vehicle type, the orientation data for the end effector is used at respective working points of arbitrary sites, for example, a window frame, of a second vehicle type.